CMA V, p. 115 - 116:Feeling is a universal mental factor, the cetasika with the function of experiencing the "flavor" of the object. Since some sort of feeling accompanies every citta, feeling serves as an important variable in terms of which consciousness can be classified. The main concern (of the Abhidhamma) is to classify the totality of cittas by way of their concomitant feeling.

Feeling may be analyzed as either threefold or fivefold. When it is analyzed in terms of its affective quality, it is threefold: pleasant, painful, and neither-painful-nor pleasant. In this threefold classification, pleasant feeling includes both bodily pleasure and mental pleasure or joy , and painful feeling includes both bodily pain an mental pain or displeasure.

When feeling is analyzed by way of the governing faculties(indriya), it becomes fivefold. These five types of feeling are called faculties because they exercise lordship or control(indra) over their associated states with respect to the effective mode of experiencing the object.

When the fivefold analysis of feeling is considered, the pleasant feeling of the threefold scheme becomes divided into pleasure and joy, the former bodily and the latter mental; the painful feeling of the threefold scheme becomes divided into pain and displeasure, again the former bodily and the latter mental; and neither-painful-nor pleasant becomes identified with equanimity or neutral feeling.

In the Suttas the Buddha sometimes also speaks of feeling as twofold, pleasure(sukha) and pain(dukkha). This is a loose or metaphorical method of analysis, arrived at by merging the blameless neutral feeling in pleasure and the blameworthy neutral feeling in pain. The Buddha further declares that whatever is felt is included in suffering(ya.m ki~nci vedayita.m dukkhasmi.m, S.36:11/iv, 216). In this statement the word dukkha does not bear the narrow meaning of painful feeling, but the broader meaning of the suffering inherent in all conditioned things by reason of their impermanence.

Pleasure(sukha) has the charactrisitic of experiencing a desirable tangible object, the function of intensifying associated states, manifestation as bodily enjoyment, and its proximate cause is the body faculty.Pain(dukkha) has the charactrisitic of experiencing an undesirable tangible object, the function of withering associated states, manifestation as bodily affliction, and its proximate cause is also the body faculty.Joy(somanassa) has the charactrisitic of experiencing a desirable object, the function of partaking of the desirable aspect of the object, manifestation as mental enjoyment, and its proximate cause is tranquillity.Displeasue (domanassa) has the charactrisitic of experiencing an undesirable object, the function of partaking of the undesirable aspect of the object, manifestation as mental affliction, and its proximate cause is the heart-base(hadayavatthu).Equanimity(upekkhaa) has the charactrisitic of being felt as neutral, the function of neither intensifying nor withering associated states, manifestation as peacefulness, and its proximate cause is consciousness without zest.************ Love Buddha's dhamma,yawares/sirikanya